#include<iostream>
#include<algorithm>
using namespace std;
const int N=1100;
int f[N][N];
char a[N],b[N];

int main(){
    int n,m;
    cin>>n>>a+1;
    cin>>m>>b+1;
    
    for(int i=0;i<=m;i++)f[0][i]=i;
    
    for(int i=0;i<=n;i++)f[i][0]=i;
    
    for(int i=1;i<=n;i++){
        for(int j=1;j<=m;j++){
            f[i][j]=min(f[i-1][j]+1,f[i][j-1]+1);
            if(a[i]==b[j])f[i][j]=min(f[i][j],f[i-1][j-1]);
            else f[i][j]=min(f[i][j],f[i-1][j-1]+1);
        }
    }
    cout<<f[n][m];
    
    return 0;
}
